1. Field Of The Invention
The invention relates to a process for the production of .beta.,.gamma.-unsaturated .delta.-lactams from 1,3-dienes and cyanogen chloride. The lactams produced according to the invention are represented by the general formula: ##STR1## wherein R.sup.1 and R.sup.2 are either independent of one another and each is hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylthio, arylthio or trialkylsilyloxy or together form a methanediyl or ethanediyl group, i.e., a --(CH.sub.2).sub.n -bridge wherein n is 1 to 2, R.sup.3 and R.sup.4 are independent of one another and each is hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylthio, arylthio or trialkylsilyloxy and R.sup.5 and R.sup.6 are either independent of one another and each is hydrogen, alkyl, aryl, alkoxy, aryloxy, alkylthio, arylthio or trialkylsilyloxy or together with the two carbon atoms of the lactam ring connected by the double bond form a carbocyclic or heterocyclic ring having 5 to 8 ring members. An especially preferred product of the process according to the invention is 2-azabicyclo[2.2.1]hept-5-en-3-one, that represents the case where R.sup.1, R.sup.2 =--CH.sub.2 --and R.sup.3 =R.sup.4 =R.sup.5 =R.sup.6 =H of the general formula I.
2. Background Art
2-Azabicyclo[2.2.1]hept-5-en-3-one is a bicyclic lactam that is suitable as the initial material for the synthesis of carbocyclic nucleoside analogs [S. Daluqe and R. Vince, J. Org. Chem., 43, (1978), pages 2311 to 2320]. Such nucleoside analogs are of interest for their antiviral and chemotherapeutic properties as potential antitumoral agents. A known synthesis of 2-azabicyclo[2.2.1]hept-5-en-3-one is based on the Diels-Alder reaction of cyclopentadiene with p-toluene sulfonyl cyanide. In such case, a tosyl-azanorbornadiene first results that is converted by acid or alkaline hydrolysis into the target compound [J.C. Jaot and A.M. van Larsen, J. Org. Chem., 39. (1974), pages 564 to 566; S. Daluoe and R Vince, loc. cit.]. Drawbacks of such process are the explosiveness of p-toluene sulfonyl cyanide and the unfavorable quantitative ratio of the product to the waste product p-tolylsulfinyl-p-tolylsulfone. Moreover, the cyclopentadiene is used in great excess which must be distilled off before the hydrolysis.